Ventilation or Filtration? The Use of Gas-Phase Air Filtration for Compliance with ASHRAE Standard 62

Abstract

ABSTRACT ASHRAE Standard 62, in its current form, employs two procedures to provide acceptable indoor air quality (IAQ) in buildings. These are the Ventilation Rate and Indoor Air Quality (IAQ) Procedures. This standard further endeavors to achieve the necessary balance between IAQ and energy consumption by specifying minimum ventilation rates and IAQ that will be acceptable to human occupants. The Ventilation Rate Procedure provides only an indirect solution for the control of indoor contaminants. While it does allow for the use of cleaned, recirculated air, it does not allow the use of this air to reduce the amount of outdoor air specified in the standard. If this air is to be used to reduce the amount of outdoor air required, or for the implementation of energy conservation measures, the IAQ Procedure must be used. The IAQ Procedure provides a direct solution by reducing and controlling the concentrations of air contaminants, through air cleaning, to specified levels. This procedure allows for both quantitative and subjective evaluation of the effectiveness of the air cleaning method(s) employed. The standard acknowledges that air cleaning, along with recirculation, is an effective means for controlling contaminants when using the IAQ Procedure. Employing this procedure allows the amount of outside ventilation air to be reduced below standard levels if it can be demonstrated that the resulting air quality meets the required criteria. More buildings are using, or will be using, gas-phase air filtration as part of their overall design for providing and maintaining acceptable IAQ. This trend is being seen in retrofit applications as well as new construction. Among the driving forces behind this are the increased awareness of people to their environment and how it may affect their well-being, legislative actions that are in effect or have been proposed, and, of course, members of the legal community litigating complaints of sick building syndrome (SBS) and building-related illness (BRI). This paper will focus on the use of gas-phase air filtration for compliance with ASHRAE Standard 62 by using the IAQ Procedure. It will cover the requirements of using this procedure, the information required, and will describe several projects where this procedure was successfully used to realize both acceptable IAQ and energy savings.